Saturation-dip measurements for the ν_8 C-O stretching band of CH_3OH with a CO_2-laser-microwave-sideband spectrometer

Rotation–torsion–vibration term-value mapping for CH3OH: Torsion-mediated doorways and corridors for intermode population transfer

“…In the linelist in the Supplementary data, the transmittances are labeled as OttA for the NRC spectrum recorded at 13.5 Pa pressure and 2.0 m path, as OttB for the NRC spectrum at 100 Pa pressure and 2.0 m path, and as Gies for the Giessen spectrum recorded at 25 Pa pressure and 16.3 m path [7]. Recent precise sub-Doppler CO 2 -laser/microwave-sideband Lamb-dip measurements for CH 3 OH [12][13][14]17,24] showed that our earlier calibration in the 10 lm region [6] should be updated by dividing the reported wavenumbers by a factor of 1.000000122, and our line list in the Supplementary material has had that correction applied for the Ottawa spectra in the 930-1230 cm À1 region.…”

“…Since then, the CO stretch has been explored in great detail by a variety of high-resolution techniques, and studies have also been extended to other vibrational modes and isotopic species. Results up to 1995 for CH 3 OH were reviewed in a monograph by Moruzzi et al [10], and a number of further studies have since been reported (see [1][2][3][4][5][6][7] and [11][12][13][14][15][16][17] for example, plus references therein). In their book, in addition to extensive tables of rotation-torsion energies for the ground vibrational state, Moruzzi et al also presented term values for many excited m 8 CO-stretching substates as well as several substates of the m 7 in-plane CH 3 -rocking mode [10].…”

The rotational spectrum of methanol in the third excited torsional stateThis article is part of a Special Issue on Spectroscopy at the University of New Brunswick in honour of Colan Linton and Ron Lees.We dedicate this paper to Dr. R.M. Lees, one of the early pioneers of methanol spectroscopy and internal rotation theory. Indeed, inspired by his 1968 methanol paper (Lees and Baker. J. Chem. Phys. 48, 5299 (1968)), numerous methanol studies have been matured and brought to the next level of ever chal

“…In the absence of a loop, the accuracy of the sub-band origin is entirely determined by the assigned accuracy of any TuFIR data or the infrared data in the absence of TuFIR transitions. The K = -5 E-state sub-band, which is directly connected to the ground state with high accuracy measurements [13], was fit with the derived energy levels directly, and should be accurate in an absolute sense. However, predictions derived from other energy levels calculated from the provided constants may be shifted by a fixed amount because of the band origin uncertainty.…”

“…A few b-type v t = 3 transitions and a few c-type v t = 3-2 transitions were reported in a tunable infrared (TuFIR) study [12]. Most recently, Sun et al recorded a number of subDoppler E-state K = -5 v t = 0 to v t = 3 transitions, which are allowed because of mixing with the C-O stretch v t = 0 E-state K = -5 levels, with a side-band laser [13].…”

Far-Infrared Laser Assignments for Methylamine

“…In this mode, we obtained saturation-dip spectra for a substantial number of the CH 3 NH 2 IR lines. The Lamb-dip resolution is of order 0.4 MHz with absolute accuracy of about 200 kHz, as determined from a study of the methanol C-O stretching spectrum [15].…”